Improvement in surveying-instruments



2 Sheets-Sheet 2. T. F. RANDOLPH. Surveying-Instrument.

No. 216,759. Patented June 24,1879.

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UNITED STATES PATENT OFFICE.

THEODORE F. RANDOLPH, OF CINCINNATI, CHIC.

IMPROVEMENT IN SURVEYING-INSTIRUMENTS.

Specification forming part of Letters Patent No. 216,759, dated J une 24, 1879; application lilcd September 2, 1878.

above the same; and my improvements are devised for the purpose of bringing the essential members of such instrument within more compact dimensions, and at a cost but little lexceeding that of the common sight compass.

The above objects I attain by devices which enable the easy separation of the telescope part from the needle-case, and the latter from its staff or tripod.

In the accompanying drawings, Figure l is a perspective view of a field-instrument embodyin g my improvements, the body or needlecase being shown detached from both the telescope and the groundsta Fig. 2 is an axial section of the instrument in the plane of the needle-lifter. Fig. 3 is a top View of the needle-case, portions of the latter being broken away. Fig. 4 is a transverse section of the telescope at the line x m of Fig. 2. Figs. 5 and 6 are full-sized representations of my key. Fig. 7 is a vertical section through the needle-lifter. Fig. 8 is an axial section through the needlecase in the plane of the clamp.

The body or needle-case A may comprise a customary socket plate, A', dialplate A, bezel A', and the usual glass pane or guard B. The dial-face may have the usual cardinal lines, graduated circle, and Vernier scale, also the customary levels C, and magnetic needle, with a suitable needle-lifter, E. The levels maybe adjusted to true horizontality by set-screws c in the face of the dial. The out keeperdisk may have a notched margin, accessible through au opening in the case, as at F. The plate A may have a tapering socket, G, for a J acobs staff, H, having an oritice, h, to receive a spring-catch bolt, I.

Y represents the square head or arbor of a pinion, which gears in a circular rack of the which transmits the motion of the screw E',

operates to instantly retract the piston o on the withdrawal of the hand of the operator. This piston appendage to the permanent lifter affords a means for temporarily checking the oscillations of the needle without necessitating any additional perforation in the casing.

The standard or pedestal J of the telescope K is so attached to the needlecase as to be readily separable therefrom. For this purpose said standard is provided with two downwardly-diverging limbs, as represented,which terminate in feet O O', having slots o o for the reception of thumbscrews N N', which screw into the under side of the plate A. Dowels or steady-pins X, projecting upward from the feet O O and entering sockets a a in the plate A, insure the proper location of the standardthat is to say, such as will bring the optical axis in the plane of the vertical axis and the zero-point of the magnetic variation vernier without special care or attention ofthe user.

Projecting from the standard J at right zingles t-o the last-mentioned plane is the bearing or socket L for the telescope neck or trunnion M.

The principal tube K and the trunnion M of the telescope constitute integral parts ot' oneV casting, preferably of brass.

The crosswires u, instead of being located in the body or principal tube, and requiring special adjustment therein, are attached to an annulus or diaphragm, U, secured within the tube V of the eye-piece at the exact focus of the eye-lens W.

Y represents the square-headed arbor of a4 pinion, y, which gears in the customary circular rack of the dial-plate A. Z represents Vernier.

l represents four screws, by means of which the eye-piece is eolliinated to the optical axis.

T is a square-headed arbor, terminating in teriorily in a pinion, 2, which, gearing in a rack, 3, upon the eye-piece, enables the latter to be adjusted tofocus.

I provide a key or Wrench, R, to enable the user to operate the various square-headed arbors, which, for the sake ot'.eco1loniy and compaetness, take the place, in my improvement, of the customary milled heads. This key is provided with studs r to enable the user to loosen or tighten the screws N N'7 and with sockets r r" for the several square-headed arbors E', Y, Z, and T, and a blade, 1"", for operating the various nicked screws, such as l and c, while orifices riv and r" enable the straightening of such parts as the needlelpoint D and piston c.

I claim as new and of my invention-.- 1. The described separable telescope-standard J, whose feet O O have steadying-pins X X', which enter sockets a a' in plate A', and slots o o' for thumb-screws N N', or their equivalents, all combined and operating substantially as set forth.

2. A needle-lifting screw inclosing a selfretracting piston, c, as and for the purpose set forth.

3. The out-keeper F, located in the main dial-plate, and having` the notched margin, operated through an opening` in the dial-case, substantially as set forth.

In testimony of which invention I hereunto set my hand.

THEODORE F. RANDOLPH.

Attest:

GEO. H. KNIGHT, W. T. JUDKINs. 

